The present invention relates to a metal laminate gasket with a coating layer to securely seal around holes of the engine, in particular a cylinder head gasket for securely sealing around cylinder bores and fluid holes.
An automobile engine has been developed to provide light weight and high power, while the engine lasts long without serious trouble, such as leaking of gas or fluid. In view of these requirements, a gasket to be installed in the engine must have light weight and seal properly around cylinder bores and fluid holes.
In view of these requirements, gaskets formed of two plates were proposed, for example U.S. Pat. Nos. 4,823,399 and 4,995,624 and Japanese Utility Model Publication (KOKOKU) No. 3-22539.
As shown in FIG. 3, a gasket as disclosed in U.S. Pat. No. 4,823,399 is formed of an upper plate 10 having a hole 11 for a cylinder bore and a hole 12 for a water hole, a lower plate 13 having a hole 14 for the cylinder bore and a hole 15 for the water hole, and coating layers 16 formed on both sides of the lower plate 13. The upper plate 10 includes a curved portion 10a and a flange 10b, which seal around the hole 11, while the lower plate 13 includes a bead 13a formed around the hole 15 and located inside the hole 12. In this gasket, when surface pressures around the cylinder bore or the water hole are changed, it is required to change a size of the curved portion 10a or the bead 13a, or the thickness of the plates 10 or 13.
In U.S. Pat. No. 4,995,624, although a wide surface pressure is formed around a cylinder bore by an embossed portion with a bead, the surface pressure around the cylinder bore is not easily regulated.
In view of the foregoings, the present invention has been made.
An object of the invention is to provide a metal laminate gasket, which can securely seal around cylinder bores and fluid holes.
Another object of the invention is to provide a metal laminate gasket as stated above, wherein the required surface pressures can be formed around the cylinder bores and fluid holes.
A further object of the invention is to provide a metal laminate gasket as stated above, wherein the plates for constituting the gasket can be easily assembled.
Further objects and advantages of the invention will be apparent from the following description of the invention.